A time division blending system is described in U.S. Pat. No. 4,004,884. In such system, different fluids from a plurality of reservoirs are blended sequentially opening and closing valves in the outlet lines leading from each reservoir for a fixed time ratio of the total valve cycle period. The amount of each different fluid obtained in the final fluid stream is directly proportional to the time the corresponding valve is open during said cycle. One is thus able to obtain reproducible and highly accurate concentrations of a number of different fluids in the final fluid system.